Hydraulically powered percussion drill
AssigneeDresser Industries, Inc.
InventorJacob Edward Feucht
Life of this patent
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Abstract
The improved hydraulically actuated percussion drill described hereinafter is designed to reciprocate a striker piston contained therein regardless of whether or not the striker piston engages the drill steel whereby vibration can be imparted to the drill. The drill includes an overtravel portion that cooperates with the striker piston to prevent metal-to-metal contact of the striker piston with the housing during operation. Means are provided to prevent the loss of fluid from the overtravel chamber whereby the striker piston will be returned to the upper end of its stroke and will not become stalled in the overtravel chamber.
Claims1
A hydraulically powered percussion drill comprising:
- an elongate housing having first and second ends, first and second chambers therein adjacent said first and second ends, a bore of smaller diameter than said first chamber extending from said first chamber through said first end, an overtravel portion in said first chamber of a diameter intermediate said bore and first chamber and first and second annular grooves in said bore spaced at a distance from said overtravel portion;
- an elongate striker piston located in said housing for reciprocating movement, said piston including a first end portion fitting closely and slidingly disposed in said bore, a second end portion partially disposed in said first chamber and extending into said second chamber and an annular flange between said end portions sized to fit relatively closely into said overtravel portion to permit restricted fluid flow thereacross, said first end portion being of smaller diameter than said second end portion;
- an annular seal located in said first annular groove in said bore in sealing engagement with said housing and the first end portion of said piston;
- a first passageway in said housing providing fluid communication between said first annular groove in said bore and a low pressure area in said drill, said passageway having one end intersecting said first groove between said annular seal and said overtravel portion;
- and
- a second passageway in said housing providing fluid communication between said second annular groove in said bore and said first chamber outside of said overtravel portion, said second passageway having one end intersecting said a second annular groove in said bore between the intersection of said first passageway with said first groove and said overtravel portion, whereby the pressure in said first chamber and overtravel portion are substantially equal, preventing stalling of said piston when said flange is in said overtravel portion.
Dependencies are inferred from the claim text.